Environmental Issues With Fish Species
One of the environmental concerns with these large scale dams is the affect they are having on the marine ecosystem in the river. The dams do not allow fish to travel upstream or downstream past the dams (Hasling, Moore, 2008, p. 339). Smaller dams use “fish ladders” to allow the fish to travel back and forth between the dam, but these dams are too large to use this concept. This is affecting many different species of fish that need to migrate during their lifespan. One of these species that is now endangered is the Chinook salmon, which spawns in the Snake River (Hasling, Moore, 2008, p. 339). Chinook salmon are born in fresh water and then after staying there for some time they move to the ocean. The Snake River is well known for its dam system, which includes numerous large dams. The dams on Snake River are preventing the salmon from being able continue their migration system (Hasling, Moore, 2008, p. 339). The dams do not allow the young salmon to travel to the ocean, which ends up killing them. Currently, there is a salmon transportation technique in place, but that is not sufficient enough in improving the Chinook salmon population (Hasling, Moore, 2008, p. 343). Because of this, the salmon were put on the list of threatened species in 1992 by the ESA and is still on that list today (Hasling, Moore, 2008, p. 339). This species of salmon as well as many others species are affected by these dams, which is a large environmental concern for the ecosystems containing dams. Various techniques are being brainstormed to fix this, but none have been put in place. Some of these options include increasing the juvenile salmon transport, reservoir drawdown, dam breaching and flow augmentation (Hasling, Moore, 2008, p. 343). Increasing the juvenile salmon transport will permit the salmon to make it to the ocean without having to get rid of or change the dams. The problem with this option is that in order to transport enough salmon to improve the population it will be very expensive (Hasling, Moore, 2008, p. 343). Second, the reservoir drawdown method would lower the dams by 35 feet for 4.5 months out of the year (Hasling, Moore, 2008, p. 343). This method will decrease the amount of hydroelectric power and also be very expensive to perform. Thirdly, dam breaching will eliminate all the hydroelectric output from the dams, but it will restore the original river and the salmon will be able to migrate like they did before the dams (Hasling, Moore, 2008, p. 344). Finally, is the flow augmentation notion. This method would change the flow of the river, so the Chinook salmon can bypass the dam in order to reach the ocean (Hasling, Moore, 2008, p. 344). The issue with this technique is that the decrease in water levels would decrease the amount of water for irrigation and other needs as well as decreasing the electricity output of the dams (Hasling, Moore, 2008, p. 344). Home Page